Experiences in early childhood have profound impacts throughout life. The long term impact of having health insurance during childhood has received little attention in the research literature, although it is known to increase children's access to medical care, and to improve childhood health and the financial circumstances of families. The goal of this project is to document the long term effects of health insurance coverage between ages 0 and 5 on health, income, and educational attainment at ages 19-43, using Medicaid as a case study. The project will consider whether the timing of exposure to health insurance through Medicaid at age 0-5 matters more to later life outcomes than exposure between ages 6-12. The federal enactment of Medicaid in 1965 and the gradual implementation of the program by the states between 1966 and 1982 will be used as a natural experiment. This period of Medicaid's history is an ideal setting to study the effects of insurance over the life course because it targeted a group in deep poverty that had few insurance alternatives. Further, it occurred sufficiently long ago to allow for follow-up well into adulthood. The project will fillan important gap in the literature by determining the long term impact of health insurance in childhood and by investigating if a public health policy can improve health and socio-economic outcomes over the life-course. The analytical strategy will use variation in the introduction of Medicaid across states between 1966 and 1982 to compare the adult outcomes for children that had different insurance exposures but were similar in other ways. Data will primarily come from the Panel Study of Income Dynamics-an on-going longitudinal study of families and their descendants that began in 1968. These data contain a rich set of health, socio-economic, and geographic variables. The panel is based on a large over sample of low-income families, making possible the study of population groups that were more likely to be affected by Medicaid's introduction. The project also will investigate if the introduction of Medicaid increase physician visits and hospital stays among children much as the program did when it was expanded in the 1980's. Fulfilling this goal is an important first step in understanding the mediating pathways that link childhood Medicaid exposure and adult outcomes. Data from the National Health Interview Survey will be used to address this question. This research is especially timely given impending implementation of national health reform which is expected to lead a broad increase in insurance coverage. PUBLIC HEALTH RELEVANCE: This project seeks to develop evidence on the long term effect of Medicaid on health, education and income over the life course. I will examine whether the effect of Medicaid varies with the age of exposure and will determine if the introduction of Medicaid in 1966 improved access to care. The work will provide important information to policy makers by filling an important gap in the literature on the long term impacts of health policy and health insurance.